External Global Stability of Back to Back MSEW

[JHeisenberg]

Looking for advice on how to model a global check of back to back MSEWs in a software like Slide or SLOPE/W. Specifically, how to set the search limits.

Example for discussion... 20' back to back MSEW. 15' between each walls reinforcing straps. 15' > 20' x 0.5 Per FHWA, active thrust can fully develop.

Option A: Model only one wall as infinite strength. 2nd wall is just modeled as retained soil. Set starting search limits at top of each wall. Failure circle is allowed to go through second wall.

Option B: Model both walls as infinite strength. Set starting search limits at top of each wall. This means failure circle can only go in the 15' space between the two walls.

Option C: ???

Personally, I lean towards option A.

 

[MTNClimber]

In Slope/W, you should model the reinforcement elements. That way, the analysis can include the failure plane through the reinforced zone. Do not model the reinforced zone to have infinite strength, since it doesn't.

 

[JHeisenberg]

I feel it is reasonable to model the MSEW as infinite strength in most cases, as the lowest failure circle is not going to go through the reinforced zone.

 

[MTNClimber]

Maybe. Maybe not. I've had the failure plane clip the lowest level of reinforcement.

It doesn't take longer than 5 minutes to model the reinforcement for a 20' tall wall to prove it. Also, now your model is more acurate.

 

[JHeisenberg]

I currently only have access to Slide and have never found a great way to do this.

 

[MTNClimber]

Sounds like you need to do a little research! I haven’t used Slide since graduate school so I’m not the best resource but I’m sure if you read through the manual and ask the software developer some questions, you’ll be able to figure it out.